Patent GB-1136363-A (GB)
Title: Apparatus for taking body fluid samples
IPC: A61M5/34
Filed: 1967-06-19
Abstract: 1,136,363. Apparatus for taking samples of body fluid. BECTON DICKINSON & CO. 19 June, 1967 [18 Aug., 1966], No.28192/67. Heading A5R. An assembly, for controlling the withdrawal of fluid (for example blood, spinal fluid or other body fluid) into a collection container, comprises a housing having a passage leading to a mounting which is arranged to receive a first cannula which will penetrate a body when the assembly is in use, a puncturable self-sealing closure carried by the housing and normally closing the passage, a second cannula having a pointed first end slidable in the passage on the side of the closure remote from the mounting for the first cannula and a pointed second end projecting from the passage and arranged to communicate with the collection container, the second cannula being axially slidable in the passage in either direction so that its first end may pierce and may be withdrawn from the closure, and stop means to limit the axial movement of the second cannula relative to the housing. As illustrated in Figure 2, on end 31 of housing 30 is mounted, for example fixedly by epoxy resin, a puncturable self-sealing closure 24 which closes a passage formed in the housing by bore 41 and first chamber 40, of which one end wall is provided by the closure. Situated within the chamber to face the closure is a pointed first end 26 of second cannula 25, the pointed second end of which projects from the passage for communication with a collection container. Mounted on the cannula to be located within the chamber is an abutment in the form of a ring 28 which engages the end walls of the chamber to provide the stop means which limits the movement of the cannula in both directions. The outer diameter of at least the part of the cannula which slides within the bore in the housing preferably is smaller than the diameter of the bore so as to provide a clearance between the cannula and the wall of the bore. On the housing is mounted, for example fixedly by epoxy resin E, end 23 of hub 21 in the other end 22 of which may be mounted, for example fixedly by epoxy resin E, a first cannula 20 having a pointed end 29 for inserting in a patient, the entire exposed portion of the first cannula being protected prior to use by a removable sheath 33 of plastics material. Defined by the closure and the hub on the side of the closure remote from the first chamber is a second chamber 42 which accommodates the first end of the second cannula after penetration of the closure, as illustrated in Figure 11 wherein the pointed end of the first cannula is shown after insertion into a vein 48 of a patient and the pointed second end 27 of the second cannula is shown after penetration through a puncturable self-sealing rubber stopper 36 of a collection container 35, which may be evacuated. In order to receive and guide the collection container into communication with the second cannula, the housing may be attached, for example by screw threads, to a holder 34 which forms a tubular extension to the housing. Figures 7 and 8 illustrate modified locations and shapes for the closure 24' and 24", respectively, and a modified shape for the abutment ring 28' of the stop means.